Water changes did not help mine at all, i adjusted my lights, as i had it for the first 6 months after setting up. I have a 215 gallon with 3 150 watt halides running now from 8-9 am, and again from 415 to 1015pm. I sucked it all out, some came back, eventually it all went away. I currently have it in my refuguium, but its staying there and not populating. The light stays on longer in there. Feeding really had no effect, i feed about 2 times a day, flake in the am, and shrimp pellets, vitamina and either frozen foods or flake seaweed at night